1. Field of the Invention
The present invention relates to a device for the electrolytic dissolution of urinary calculi and to the related method of treatment of urinary calculosis.
In particular, the present invention relates to a device which is capable of producing the electrolytic dissolution of urinary calculi, or electrolitholysis, in the urinary tract without having to resort to hospitalization of the patient.
2. Prior Art
The treatment of urinary calculosis is the subject of intense research both in the pharmacological and in the surgical field.
In the treatment of urinary calculosis, attempts have always been made to achieve dissolution of calculi rather than fragmentation, since fragmentation, even if achieved in an optimum manner, entails a high risk of retaining in the urinary cavities fragments which can constitute a nucleus for the formation of new calculi.
Dissolution of calculi by chemical means, or chemolitholysis, entails the perfusion of solutions, formulated appropriately according to the composition of the calculus to be treated, along the urinary tract proximate to the body region where the calculus is located.
In performing chemolitholysis, appropriately shaped tubes are inserted endoscopically or percutaneously and then a solution that contains active principles, selected appropriately according to the composition of the calculus to be dissolved, is perfused.
The chemical dissolution method, however, has not yielded satisfactory results, since it requires long treatment times which make it poorly tolerated by patients. The person subjected to the treatment furthermore complains of pains and burning sensations due to the damaging and irritating action which the perfused pharmacological solutions induce at the level of the epithelium that lines the urinary tract.
In the field of the fragmentation of calculi by applying energy in the form of shock waves, ultrasound or electrohydraulic waves, many methods and devices have been recently devised and improved which have allowed to break up a calculus both from outside the human body (extracorporeal shock wave lithotripsy or ESWL) and by introducing operating instruments percutaneously or endoscopically in the urinary cavities (PCNL and URSL).
These recent methods, however, are not free from drawbacks, which are mainly due to imperfect fragmentation of the calculus, consequently forming fragments which inside a renal calyx can constitute a nucleus for the precipitation and aggregation of crystals, causing regrowth of the calculus and relapse of the lithiasic disorder a short time after. These drawbacks occur mostly after extracorporeal treatments.
Moreover, some calculi which have a particular chemical composition, such as for example cystine and calcium oxalate monohydrate calculi, are particularly resistant to the action of shock waves and in the best of cases can be fragmented only into large fragments which are impossible to expel.
The need is therefore currently felt, in the field of microinvasive surgery, to have methods and devices which lead to complete freedom from calculi (calculus-free status) without the need for hospitalization and anaesthesia.